1. Field of the Invention
The present invention relates to improvements to a tracking-type solar module for generating power while tracking sunlight.
2. Description of the Related Art
Since solar cells are generally expensive, converging solar modules have previously been suggested in order to reduce costs. Such converging solar modules must track the changes in sunlight at each moment and move a solar cell in compliance with the position of the sunlight while receiving the sunlight.
FIG. 16 depicts the movement of the sun during a single day as well as changes in the sun's orbit for each season. As the diagram shows, the sun moves through a variety of positions depending on time and season. A system is already known using programmable tracking for tracking the sun as it moves wherein tracking speed and such like are calculated beforehand in accordance with the sun's movements, and the sun is tracked along a path determined based on these calculations.
However, such programmable tracking has a disadvantage that a high degree of accuracy is required for setting the compass points and the horizontal level when installing the solar cell.
As a result, there is a problem that errors accumulate over a long period of use. There is also a problem that lines become complex when controlling unequal speeds.
A sensor-system tracking has therefore been proposed for detecting the position of the sun by means of a sensor and carrying out tracking based on a position detection signal from this sensor. Since no errors are accumulated when a sensor system is used, tracking with a high degree of accuracy can be achieved relatively easily without the prerequisite of high accuracy during installation.
Conventional converging solar modules track the sun using the system described above while converging sunlight with a lens, thereby reducing the working area of the solar cell and lowering costs.
However, when sunlight is converged in this manner, there is the problem that the temperature of the solar cell rises, reducing power generation efficiency. The solar cell must therefore be cooled to lower the temperature. A cooling method for a solar cell such as this was disclosed in Japanese Patent Laid-Open Publication No. Hei 5-332636. This method, whereby a solar cell is cooled indirectly with a cooling medium through an insulating film, constitutes related art of the present publication.
However, the above-mentioned system had the disadvantage that, since the cooling of the solar cell with a cooling medium is not performed directly but indirectly through an insulating film, adequate cooling effect cannot be obtained when the convergence level is increased.
An additional problem is that, when the sensor system described above is used for tracking the sun, errors are liable to occur as when, for instance, sunlight is obscured by clouding.